In the Third Generation Partnership Project (3GPP), which is one of the standards bodies, standardization of 3GPP Long Term Evolution (LTE) Rel-10 (later systems may also be referred to as LTE Advanced (LTE-A)), which is one of the fourth generation mobile communication systems, is almost completed, and currently, standardization of LTE Rel-11 that is an extension thereof is being performed.
In an up link (communication from a mobile station apparatus (user equipment: UE) to a base station apparatus) of LTE Rel-11, a heterogeneous network to install a macro base station (enhanced node B: eNB) that covers a relatively wide range, an LPN (low power node, radio remote head: RRH) that covers a narrow range in an area covered by a macro base station (may be referred to as a macro area), and the like is currently under review.
In a heterogeneous network, it is possible to reduce influence of the interference between a macro base station and an LPN or between an LPN and an LPN, not only by cell splitting gain obtained by carrying out control respectively as separate base stations, but also by cooperation. Such technique is called as coordinated multi-point transmission and reception (COMP) and is under a variety of review.
Further, supporting different coverage with up and down links is also under review, and in order to achieve these issues at the same time, use of a reference signal parameter unique to a mobile station apparatus is under review (NPL 1).